1. Field of the Invention
The present invention relates to an actuator, in particular, to an actuator with a quick-release mechanism.
2. Description of Related Art
Linear actuators are commonly used in applications such as electric medical beds, treadmills and wheelchairs for adjusting and shifting the elevation positions and elevation angles thereof. For emergency purposes of patient treatments, the use of actuator with a quick-release mechanism allows the medical bed to be adjusted and shifted rapidly such that precious time crucial in medical emergencies can be saved, which is an important objective of the present invention.
A known actuator with a quick-release mechanism is disclosed in such as Chinese Patent Publication No. CN100552263C comprising an electric motor, a transmission mechanism and a quick-release mechanism. The electric motor comprises a main body and a worm shaft extended outward from a center of the main body. The transmission mechanism comprises a lead screw shaft and a worm gear mounted on one end of the lead screw shaft and engaged for transmission with the worm shaft. The quick-release mechanism comprises two cylindrical connection parts; wherein one cylindrical connection part is firmly attached to the lead screw shaft to rotate together with the lead screw shaft and another cylindrical connection part is firmly attached to the worm gear to rotate together with the worm gear. The corresponding end of each one of the cylindrical connection parts is provided with a torque transmission unit. By utilizing the engagement and disengagement between the cylindrical connection parts, the lead screw shaft and the worm gear can be either engaged with each other for transmission or disengaged from each other for transmission.
Nevertheless, the known actuator with a quick-release mechanism shows the following drawbacks during its actual operation and use. Such known actuator is of a complicated structure involving a great number of components, which poses difficulties to the assembly thereof and requires greater costs in the material and manufacturing the components as well as the overall production costs of the actuator. Furthermore, the method of push used to actuate the engagement and disengagement of the cylindrical connection parts tends to generate a relatively small reaction force, which leads to inconvenience to the use and operation of the actuator.